title: Detection of nonlinearity in the healthy heart rhythm.
abstract: Sequences of interbeat intervals from two groups of subjects, 24 in relaxed and 10 in sleeping condition were analyzed by the nonlinear predictor method as well as by a method, proposed recently, able to directly estimate the time series nonlinearity. The nonlinear predictability of the R-R intervals is tested by using surrogate data. The results obtained with both methods show that nearly all the sequences exhibit a statistically meaningful degree of nonlinearity. This raises the question whether such nonlinearity encodes information about the physiological condition of the examined subjects.
authors.affiliation: Institute of Biophysics, CNR, Pisa, Italy. chillemi@ib.pi.cnr.it
authors.forename: S
authors.initials: S
authors.lastname: Chillemi
authors.forename: M
authors.initials: M
authors.lastname: Barbi
authors.forename: A
authors.initials: A
authors.lastname: Di Garbo
authors.forename: R
authors.initials: R
authors.lastname: Balocchi
authors.forename: C
authors.initials: C
authors.lastname: Michelassi
authors.forename: C
authors.initials: C
authors.lastname: Carpeggiani
authors.forename: M
authors.initials: M
authors.lastname: Emdin
mesh_terms: D015716:Electrocardiography, Ambulatory; D006339:Heart Rate; D006801:Humans; D017711:Nonlinear Dynamics; D012815:Signal Processing, Computer-Assisted; D012890:Sleep / Q000502:physiology